Spray nozzle



B. B. DUNN SPRAY NOZZLE Nov. 6, 1956 Filed Sept. 3, 1953 lnnxHllllIIlllll nwxrr lignea/5.01m? gy wv/M United States Patent O SPRAY NOZZLE Byron B. Dunn, Cambridge, Mass., assignor to National Gunite Corporation, Boston, Mass., a corporation of Massachusetts Application September 3, 1953, Serial No. 378,199 1 Claim. (Cl. 299-140) This invention relates to spray nozzles and more particularly to an improved nozzle for spraying viscous and semi-liquid materials such, for example, as vinyl solution or plastic paint containing fine sand or other aggregate. I have found -that the feeding ow and spraying of such materials are facilitated by movement of the materials along a straight path to and concentric with the spraying nozzle. The even `and uniform flow of such materials through 'the nozzle is also facilitated by maintaining the nozzle iiow passage free from obstruction by the viscous material and aggregates `and an important feature of my invention relates to a rotary adjustable nozzle that aids this function. My improved rotary nozzle furthermore provides for a total closure of the ow of material through the nozzle when desired whereas the coarse aggregate has prevented such closing in nozzles heretofore employed. Other novel fea-tures of the invention are hereinafter more specifically described.

These and other features of the invention will be more readily understood and lappreciated from the following detailed description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawing wherein my improved nozzle construction is illustrated in side elevation and longitudinal section.

In the drawing, indicates a substantially straight pipe for conducting compressed air to the nozzle. Disposed parallel with and concentrically surrounding the pipe 10 is a larger pipe 12 providing a material feed chamber 14 therebetween. Both pipes have open forward ends and as illustrated in the drawing the inner pipe extends in uniform bore diameter outwardly of and beyond the outer pipe. The end of the outer pipe 12 is externally threaded at 16 to receive in threaded engagement thereon the rear cylindrical portion 20 of a nozzle 18. The nozzle 18 embodies a conical portion 22 loca-ted forwardly of the cylindrical portion 20 and tapering inwardly about and adapted to cooperate with the open end of the inner pipe 10 to control the spray material passing through the nozzle from the chamber 14. The nozzle also preferably includes a smaller cylindrical portion 24 located forwardly of the conical portion 22 and having an inner diameter approximating the inner diameter of the pipe 10, and an outwardly-forwardly iiaring spray directing conical portion 26 is preferably provided on the nozzle forwardly of the cylindrical portion 24. The conical portion 22 tapers inwardly to a bore diameter approaching that of the inner pipe 10 yand the nozzle end of the inner pipe terminates in a circular rim having an 2,769,670 Patented Nov. 6, 1956 ICC -outer annular edge 28 making an angle directed toward the inner surface of the conical portion 22 and adapted to make annular line contact therewith and thus completely close the nozzle end of the chamber 14 when the nozzle is screwed rearwardly on the outer pipe 12 into contact with the end of the inner pipe.

The viscous and aggregate-containing material to be sprayed is fed forwardly into and through the chamber 14 and is projected outwardly through the nozzle by compressed air flowing from the pipe 10. The material flows in a straight path throughout its movement and the amount of material passing through the nozzle is controlled merely by rotatably adjusting the nozzle 18 to vary the annular Igap between the conical portion 22 and the end of the pipe 10. The rotary action of the nozzle is adapted to aid in keeping the nozzle free from yobstruction by dislodging aggregate that might otherwise become clogged in the relatively narrow gap, and this function is more particularly useful when fully closing the nozzle. Nozzles which close with a surface contact or operate with a straight line motion and without rotary action cannot fully and completely close since some of the aggregate is always trapped between the cooperating parts at the gap. The line contact made by the edge 28 together with the rotary action of the nozzle serve to dislodge this aggregate and permit the nozzle to close tightly onto the pipe 10 in a manner providing a total closure permitting no drip. Thus the tlow of aggregate-containing spray material can be entirely controlled at the nozzle which is usually located a substantial distance from the source of supply. The cylindrical portion 24 `and the outwardly flaring flange 26 of the nozzle serve to aid in directing the spray into an annular path through the portion 24 and from thence outwardly in the diverging spray illustrated in the drawing.

Having thus disclosed my invention what I claim as new and desire to secure by Letters Patent is:

A spray nozzle for viscous, semi-liquid and aggregatecontaining materials, comprising an inner air conducting pipe of uniform bore throughout and having an open nozzle end, a larger outer pipe concentrically surrounding the inner pipe and providing a material feeding chamber therebetween, the outer pipe having an open nozzle end disposed rearwardly of the nozzle end of the inner pipe, and -a nozzle having a rear cylindrical portion larger than and threaded to the nozzle end of the outer pipe and a conical portion tapered inwardly-forwardly therefrom about the nozzle end of the inner pipe to a bore diameter approximating that of the inner pipe, the nozzle end of the inner pipe terminating in a rim having an outer annular edge making an angle directed toward said conical portion of the nozzle and adapted to make annular line contact therewith and tightly close the nozzle end of said chamber when the nozzle is threaded rearwardly on the outer pipe into contact with the inner pipe.

References Cited in the tile of this patent UNITED STATES PATENTS 894,069 Schurs July 21, 1908 1,268,232 Furman June 4, 1918 1,989,696 Kelley Feb. 5, 1935 2,259,215 Scheurer Oct. 14, 1941 2,600,040 Widmayer June 10, 1952 

